package task

import (
	"context"
	"fmt"
	"sync"
	"time"
	"xagent/internal/memory"
	"xagent/internal/types"
	proto "xagent/proto/v1"

	"github.com/asynkron/protoactor-go/actor"
)

// ResourceMetrics tracks resource usage and availability
type ResourceMetrics struct {
	CPUUsage    float64
	MemoryUsage float64
	LoadFactor  float64
	LastUpdate  time.Time
}

// ResourceAllocation represents allocated resources for a task
type ResourceAllocation struct {
	TaskID      string
	CPULimit    float64
	MemoryLimit float64
	Priority    types.Priority
	StartTime   time.Time
	EndTime     time.Time
}

// MCTSNode represents a node in the Monte Carlo Tree Search
type MCTSNode struct {
	state    *TaskContext
	parent   *MCTSNode
	children []*MCTSNode
	visits   int
	value    float64
	untried  []*Task
	action   *Task
}

// TaskProcessor handles intelligent task processing and decision making
type TaskProcessor struct {
	manager         *TaskManager
	memoryManager   memory.MemoryManager
	resourceMetrics *ResourceMetrics
	allocations     map[string]*ResourceAllocation
	mutex           sync.RWMutex
	maxConcurrent   int
}

// NewTaskProcessor creates a new task processor
func NewTaskProcessor(manager *TaskManager, memoryManager memory.MemoryManager, maxConcurrent int) *TaskProcessor {
	return &TaskProcessor{
		manager:         manager,
		memoryManager:   memoryManager,
		resourceMetrics: &ResourceMetrics{},
		allocations:     make(map[string]*ResourceAllocation),
		maxConcurrent:   maxConcurrent,
	}
}

// ProcessTask processes a task with intelligent resource allocation
func (tp *TaskProcessor) ProcessTask(ctx context.Context, task *Task) error {
	// Evaluate task and allocate resources
	score := tp.evaluateTask(task)
	allocation := tp.calculateResourceAllocation(score)

	// Execute task with allocated resources
	if err := tp.executeTask(ctx, task, allocation); err != nil {
		return fmt.Errorf("task execution failed: %w", err)
	}

	return nil
}

// ProcessActorTask processes a task using the actor system
func (tp *TaskProcessor) ProcessActorTask(ctx context.Context, task *Task, actorSystem *actor.ActorSystem, supervisor *actor.PID) error {
	score := tp.evaluateTask(task)
	allocation := tp.calculateResourceAllocation(score)

	if err := tp.executeTask(ctx, task, allocation); err != nil {
		return fmt.Errorf("actor task execution failed: %w", err)
	}

	return nil
}

// evaluateTask evaluates a task's priority and resource requirements
func (tp *TaskProcessor) evaluateTask(task *Task) float64 {
	var score float64 = 1.0

	// Factor 1: Priority
	score *= float64(task.Priority) / 4.0

	// Factor 2: Resource requirements
	if task.Metadata != nil && len(task.Metadata.RequiredResources) > 0 {
		resourceScore := tp.evaluateResourceEfficiency()
		score *= resourceScore
	}

	// Factor 3: Dependencies
	if task.Metadata != nil && len(task.Metadata.Dependencies) > 0 {
		depScore := tp.evaluateDependencies(task.Metadata.Dependencies)
		score *= depScore
	}

	return score
}

// evaluateDependencies evaluates task dependencies
func (tp *TaskProcessor) evaluateDependencies(deps []string) float64 {
	if len(deps) == 0 {
		return 1.0
	}

	completedDeps := 0
	for _, depID := range deps {
		if task, err := tp.manager.GetTask(depID); err == nil && task.Status == proto.TaskStatus_TASK_STATUS_COMPLETED {
			completedDeps++
		}
	}

	return float64(completedDeps) / float64(len(deps))
}

// evaluateResourceEfficiency evaluates resource usage efficiency
func (tp *TaskProcessor) evaluateResourceEfficiency() float64 {
	tp.mutex.RLock()
	defer tp.mutex.RUnlock()

	if tp.resourceMetrics == nil {
		return 1.0
	}

	// Calculate efficiency based on current resource usage
	cpuEfficiency := 1.0 - tp.resourceMetrics.CPUUsage
	memEfficiency := 1.0 - tp.resourceMetrics.MemoryUsage

	return (cpuEfficiency + memEfficiency) / 2.0
}

// calculateResourceAllocation calculates resource allocation based on score
func (tp *TaskProcessor) calculateResourceAllocation(score float64) *ResourceAllocation {
	tp.mutex.Lock()
	defer tp.mutex.Unlock()

	// Base allocation
	allocation := &ResourceAllocation{
		CPULimit:  0.2 + (score * 0.3), // 20-50% CPU
		StartTime: time.Now(),
	}

	// Adjust based on system load
	if tp.resourceMetrics.LoadFactor > 0.8 {
		allocation.CPULimit *= 0.8 // Reduce allocation under high load
	}

	return allocation
}

// executeTask executes a task with allocated resources
func (tp *TaskProcessor) executeTask(ctx context.Context, task *Task, allocation *ResourceAllocation) error {
	tp.mutex.Lock()
	tp.allocations[task.ID] = allocation
	tp.mutex.Unlock()

	defer func() {
		tp.mutex.Lock()
		delete(tp.allocations, task.ID)
		tp.mutex.Unlock()
	}()

	// Update resource metrics
	tp.updateResourceMetrics(allocation)

	// TODO: Implement actual task execution logic
	time.Sleep(100 * time.Millisecond)

	return nil
}

// updateResourceMetrics updates resource usage metrics
func (tp *TaskProcessor) updateResourceMetrics(allocation *ResourceAllocation) {
	tp.mutex.Lock()
	defer tp.mutex.Unlock()

	tp.resourceMetrics.CPUUsage += allocation.CPULimit
	tp.resourceMetrics.LastUpdate = time.Now()
}

// TaskContext represents the context for task execution
type TaskContext struct {
	Task           *Task
	Dependencies   []*Task
	RelatedTasks   []*Task
	PastExperience []memory.Memory
	StartTime      time.Time
	Resources      *ResourceMetrics
	Score          float64
}

// ActorTaskContext represents the context for actor-based task execution
type ActorTaskContext struct {
	*TaskContext
	ActorPID    *actor.PID
	ActorSystem *actor.ActorSystem
	Supervisor  *actor.PID
}
